The authors have developed a lesson plan on water filtration to introduce K-12 students to chemical engineering through hands-on activities. The primary motivation for developing the lesson was to hook K-12 students into the societal impact of chemical engineering in addressing the grand challenge of providing access to clean water. Our secondary motivation was to develop outreach materials related to our research on transport in pores and microchannels. The plan was developed in consultation with middle school teachers and tested in middle school classrooms and an after school program in a Boys & Girls Club. The activities have been used in several outreach activities since 2011 including multiple Girl Scout events for 6th-12th graders, a professional development workshop for K-12 science teachers, and a summer camp for 4th-8th graders and their grandparents. The lesson begins with a discussion of challenges of purifying polluted water and drinking water supplies in developing nations. Then a series of activities demonstrate how chemical engineering principles and technologies are effective in cleaning water and how they can be used to enhance access to purified drinking water. This lesson is designed to be completed in one 1-hour period with two experiments and one physical activity. In the first experiment, cornmeal is separated from water by passing water contaminated with cornmeal and food coloring through a simple filter made of a cotton ball (a paper coffee filter may also be used). This is an example of size-based mechanical filtration. In the second experiment, students learn that food coloring can also be removed from water in a process called “chemical filtration” (adsorption). Students test two types of materials: glass beads and activated carbon. Glass beads do not interact with food coloring and do not remove the coloring from water. Activated carbon interacts with food coloring and removes it from water making the water clear again. Activated carbon is a very common material for removing organic contaminants and is used in many devices, such as household water filters and pool and fish tank filters. Water pitchers with built-in filtration systems are also discussed as an optional component of this activity. The physical activity involves students hopping on one foot through pathways marked on the floor as they pretend to be contaminant molecules moving through pores in a filter. Wide and narrow pathways simulate mechanical filtration. Pathways marked with double-sided tape simulate chemical filtration. The goal of this paper is to disseminate the lesson plan and all the associated documentation to other educators.
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